BrECB2的单核苷酸突变损害了RNA编辑效率和叶绿体的早期生物合成

doi:10.1016/j.jia.2025.11.001

摘要/Abstract

摘要：

叶绿体是进行光合作用的重要器官，而光合作用对提高青梗菜产量至关重要。在本研究中，我们对白菜自交系'136'自交过程中出现的叶绿体发育延迟突变体'M136'进行了评估。M136'的新生真叶是黄色的，随着成熟逐渐变绿。M136'的叶绿体发育、色素含量和光合作用参数受到影响，并随着生长逐渐恢复，叶绿素荧光参数也受到影响。根据遗传分析和集群分离分析法（BSA）-seq，突变体的表型由一个单隐性基因控制，该基因被鉴定为BraA06g011520.3.5C（BrECB2），它编码一种DYW型五肽重复（PPR）蛋白。在'M136'中，BrECB2的第4个PPR基序中的T-to-C单核苷酸多态性（SNP）导致苏氨酸到异亮氨酸德氨基酸置换。BrECB2主要在幼叶中表达。‘M136'的叶绿体RNA编辑效率受到影响，在叶片变绿后完全恢复，在互补品系中编辑效率部分恢复。‘M136'的质体编码RNA聚合酶活性未受影响。功能互补分析表明，BrECB2的瞬时过表达部分挽救了'M136'的突变体表型和RNA编辑效率。综上所述，本研究表明BrECB2参与叶绿体早期发育和RNA编辑，为了解青梗菜叶绿体发育调控网络提供了理论依据。

Abstract:

Chloroplasts are important organelles for photosynthesis, which is essential for increasing the yields of pak choi. In this study, we evaluated a delayed chloroplast development mutant ‘M136’ identified during self-crossing of the pak choi inbred line ‘136’. The young true leaves of ‘M136’ were yellow and gradually turned green with maturation. Chloroplast development, pigment contents, and photosynthetic parameters were impaired and gradually recovered with growth in ‘M136’, and chlorophyll fluorescence parameters were also impaired in ‘M136’. Genetic analysis and bulk segregant analysis (BSA)-seq revealed that the mutant phenotype was controlled by a single recessive gene, identified as BraA06g011520.3.5C (BrECB2), which encodes a DYW-type pentatricopeptide repeat (PPR) protein. In ‘M136’, a T-to-C single nucleotide polymorphism (SNP) in the 4th PPR motif of BrECB2 caused a threonine-to-isoleucine amino acid substitution. BrECB2 was mainly expressed in young leaves. The chloroplast RNA editing efficiency of ‘M136’ was affected and significantly recovered after the leaves turned green, and the editing efficiency was partially restored in complementation lines. The plastid-encoded RNA polymerase activity was not affected in ‘M136’. Functional complementation analyses revealed that the transient overexpression of BrECB2 partially rescued the mutant phenotype and the RNA editing efficiency in ‘M136’. In summary, this study indicates that BrECB2 is involved in early chloroplast development and RNA editing, providing a theoretical basis for understanding the regulatory network involved in chloroplast development in pak choi.

Key words: pak choi , BSA-seq , BrECB2 , pentatricopeptide repeat protein , RNA editing , chloroplast development

Zifan Zhao, Feng Pan, Tianxiang Zhao, Luyao Zhang, Qingli Hou, Tian’er Tang, Nan Wang, Chong Tan, Yun Zhang, Zhiyong Liu. BrECB2的单核苷酸突变损害了RNA编辑效率和叶绿体的早期生物合成[J]. Journal of Integrative Agriculture, 2026, 25(7): 2825-2835.

Zifan Zhao, Feng Pan, Tianxiang Zhao, Luyao Zhang, Qingli Hou, Tian’er Tang, Nan Wang, Chong Tan, Yun Zhang, Zhiyong Liu. A single nucleotide mutation in BrECB2 impaired RNA editing efficiency and early chloroplast biosynthesis in pak choi[J]. Journal of Integrative Agriculture, 2026, 25(7): 2825-2835.

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